Nanotyrannus, the cheetah of the dinosaur world, was even more terrifying than the great T. rex: U of A Research

From left to right, Guaibasaurus was an early dinosaur with a low score typical of primitive forms; despite its pop culture status, Velociraptor is revealed to be among the least swift of the carnivorous dinosaurs; the Jurassic predator Allosaurus was large and moderately adapted for speed; despite its bulk, Tyrannosaurus scores high on the speed charts; the controversial species Nanotyrannus was the bipedal dino best adapted for speed – the Usain Bolt of its era. PHOTO SUPPLIED

Nanotyrannus was the cheetah of the dinosaur world, its speed making it even more terrifying than the great T. rex, suggests University of Alberta research.

When it comes to speed, the five-meter long Nanotyrannus led the pack, leaving the swift Tyrannosaurus rex and known juveniles of other tyrannosaur species in the dust. Nanotyrannus’ status as a distinct species has been debated for years due its strong resemblance to a juvenile T. rex, but its uniquely elongated limbs now indicate that Nanotyrannus really was its own distinct species.

“In terms of Cretaceous ecology, T. rex was the lion and Nanotyrannus was the cheetah. As far as I’m concerned, it was the scariest dinosaur,” says U of A paleontologist Scott Persons, who led the study in leg length among carnivorous dinosaurs as part of his doctoral research.

“Sure, it might take it four to five bites to eat you, while T. rex could do it in just one or two, but eaten is eaten — and no dinosaur was better adapted to chase you down.”

Persons’ research yielded a formula to identify adaptations for speed — to run faster, dinosaurs evolved longer legs.

“Speed determines what prey you can catch, how you hunt it, and the sort of environment that you are most successful in. That’s true for modern carnivores, and must have been true for dinosaurs,” notes Persons.

And specifically, fast-running animals, like cheetahs, have proportionately longer lower legs, from the knee down. The longer the lower leg is in comparison to the upper leg, the faster the animal is.

But there is a hitch.

Long legs are also relatively weaker and less suited to supporting great weight.

“Over evolution, you have these two conflicting forces: the need for speed and the need for weight support,” explains Persons. “You cannot just compare little dinosaurs to big dinosaurs; you have to factor out the influence of body mass.”

To do that, Persons and his supervisor, renowned paleontologist Philip Currie, spent years collecting leg measurements from more over 50 different species of predatory dinosaurs from museum collections all over the world. The dinosaurs ranged in size from smaller than a chicken to longer than a school bus.

With this data, Persons developed the equation to determine a dinosaur’s “cursorial limb proportion score,” or how strongly adapted for speed a particular dinosaur species was. The results indicate that early ancestral carnivores were generally less developed for speed and evolved to become faster over time.

The new research on dinosaur limb proportions was published this week in the peer-reviewed journal Scientific Reports.

As Advertised in the Edmonton SUN

Nanotyrannus, the cheetah of the dinosaur world, was even more terrifying than the great T. rex: U of A Research

Nanotyrannus was the cheetah of the dinosaur world, its speed making it even more terrifying than the great T. rex, suggests University of Alberta research.

When it comes to speed, the five-meter long Nanotyrannus led the pack, leaving the swift Tyrannosaurus rex and known juveniles of other tyrannosaur species in the dust. Nanotyrannus’ status as a distinct species has been debated for years due its strong resemblance to a juvenile T. rex, but its uniquely elongated limbs now indicate that Nanotyrannus really was its own distinct species.